Mute

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> SPST switch between + and - output of my differential amp and it works but seems to degrade the audio.

I hooked a switch across my 120V wall outlet. It works (the lights go off) but the power is degraded? (TV goes dead, wires get hot, fuse blows.)

There may be another way to turn off the lights?

> I know a one transistor amp is a class A, and a push pull is class AB.  Is a differential amp still class A?

Form and function are different.

A single device amplifier CAN run in A, B, or C.

But you think otherwise because you want "clean". B and C are grossly distorted. However they work very well in radio systems where only the frequency, and maybe the amplitude, are needed, the wave-shape cleaned-up with tuned circuits.

OTOH there are many push-pull class A audio amps.

Does the device current ever cut-off as signal swings?

80hinhiding said:

I haven't noticed but I think you're hinting at the mute solution.

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No, he´s hinting at what makes an amplifier class A, AB, or B instead of the circuit topology.
http://sound.whsites.net/articles/amp-classes.htm

Question: how can audio be degraded when it´s muted (sorry, probaly understood you wrong)?

L´Andratté said:

Question: how can audio be degraded when it´s muted (sorry, probaly understood you wrong)?

Click to expand...

+1

80hinhiding said:

Shorting one of the audio inputs to ground doesn't seem to work very well. 

Click to expand...

In what way does it not work well?

Try shorting inputs rather than outputs.